L50 and 54, Mastication Pt 2 and secretions in the stomach and pancreas

Question 1

L50

What are the main functions of saliva?

Answer 1

Moistens and cleanses the oral mucosa.

Cools food and assists chewing to form a bolus.

Lubricates the food (via mucins) to ease chewing, swallowing, and speech.

Solubilises food to enhance taste perception.

Begins digestion (α-amylase, lingual lipase).

Protects against bacteria (lysozymes, antibodies, lactoferrin).

Acts as an alkaline buffer (neutralises acids).

Mineralises teeth (prevents enamel demineralisation)

Question 2

L50

What enzymes are found in saliva and what do they do?

Answer 2

α-amylase: breaks down starch into maltose.

Lingual lipase: starts lipid digestion (especially important in newborns).

Question 3

L50

What antimicrobial substances are found in saliva?

Answer 3

Lysozymes: break down bacterial cell walls.

Immunoglobulins (especially IgA): immune defence.

Lactoferrin: binds iron, limiting bacterial growth.

Question 4

L50

How does saliva act as a buffer?

Answer 4

Contains bicarbonate ions (HCO₃⁻).

Neutralises acids from food or gastric reflux (vomiting).

Maintains a slightly alkaline environment in the mouth.

Question 5

L50

How does saliva help protect teeth?

Answer 5

Supplies calcium and phosphate to remineralise enamel.

Prevents acid erosion and dental caries.

Question 6

L50

What other glands contribute minor secretions to the oral cavity?

Answer 6

Numerous small glands in lips, cheeks, palate, and tongue.

Question 7

L50

What is the daily volume of saliva secretion?

Answer 7

Between 800–1500 ml/day.

Question 8

L50

What is the basic composition of saliva?

Answer 8

> 99% Water.

Ions: Na⁺, K⁺, Cl⁻, HCO₃⁻, Ca²⁺, Mg²⁺, PO₄³⁻, I⁻.

Proteins: α-amylase, lipase, mucins, immunoglobulins.

pH: 6.1–8.0, depending on flow rate.

Question 9

L50

How does salivary pH change with flow rate?

Answer 9

At rest: slightly acidic (~pH 6.1).

During stimulation (e.g. eating): becomes more alkaline (due to increased HCO₃⁻).

Question 10

L50

Why is saliva hypotonic compared to plasma?

Answer 10

Duct cells remove Na⁺ and Cl⁻ but add K⁺ and HCO₃⁻.

Ducts are relatively impermeable to water.

Result: lower ion concentration than plasma = hypotonic.

Question 11

L50

How is primary saliva formed?

Answer 11

Acinar cells secrete an isotonic fluid (similar to plasma).

Water follows ions by osmosis initially.

Question 12

L50

How is final saliva modified?

Answer 12

Ductal cells:

• Reabsorb Na⁺ and Cl⁻.
• Secrete K⁺ and HCO₃⁻.

Water does not follow because ducts are impermeable.

Question 13

L50

How does flow rate affect saliva composition?

Answer 13

FLOW RATE: Low (e.g. asleep) (IONIC CONTENT) More hypotonic (DESCRIPTION) More Na⁺/Cl⁻ removed; little HCO₃⁻.

FLOW RATE: High (e.g. eating) (IONIC CONTENT) Less hypotonic (DESCRIPTION) Less Na⁺/Cl⁻ removed; more HCO₃⁻ added for buffering.

Question 14

L50

What stimulates saliva secretion?

Answer 14

Pressure, chemoreceptors: triggered by chewing, taste, tactile stimuli.

Cortex input: thought, sight, smell of food.

Parasympathetic Nervous System: main controller (stimulates watery saliva).

Sympathetic Nervous System: can modify composition but generally reduces flow.

Question 15

L50

What is the role of the parasympathetic nerves in saliva secretion?

Answer 15

Promote vasodilation around salivary glands.

Increase transport of ions into acinar cells.

Enhance HCO₃⁻ secretion and water movement.

Stimulate enzyme (amylase) production.

Question 16

L50

What happens under sympathetic stimulation?

Answer 16

Can cause slight secretion of a thicker, more mucous-like saliva.

Overall reduces volume of saliva (dry mouth under stress).

Question 17

L50

What is salivary hypofunction and what are its causes?

Answer 17

Reduced or absent saliva production.

Causes:

• Head and neck radiotherapy.
• Autoimmune diseases (e.g. Sjögren’s syndrome, lupus, rheumatoid arthritis).
• Many medications (especially anti-cholinergics).

Question 18

L50

What are symptoms of salivary hypofunction (xerostomia)?

Answer 18

Dry mouth sensation.

Burning mouth.

Fissured, lobulated tongue.

Candida/oral yeast infections.

Dental caries.

Difficulty swallowing dry food.

Loss of taste.

Question 19

L50

Which common drugs cause xerostomia?

Answer 19

Anti-cholinergics (block parasympathetic output).

Anti-depressants (e.g. amitriptyline, fluoxetine).

Bronchodilators (e.g. salbutamol, ipratropium).

Antihistamines (e.g. diphenhydramine).

Diuretics (e.g. furosemide).

Decongestants, anti-psychotics, and many others.

Question 20

L50

How can salivary hypofunction be managed?

Answer 20

Chewing sugar-free gum.

Sucking on ice chips.

Water or glycerine sprays.

Artificial saliva substitutes.

Sialogogues (cholinergic drugs that stimulate saliva production).

Question 21

L50

Why must saliva remain hypotonic to plasma?

Answer 21

To maintain hydration of oral tissues.

If saliva were hypertonic, water would be drawn out of tongue and cheek tissues by osmosis, causing dehydration.

Question 22

L50

Why does bicarbonate (HCO₃⁻) secretion increase during eating?

Answer 22

During food intake, acid levels rise (from food and early gastric secretion).

Higher HCO₃⁻ levels in saliva neutralise acid to protect enamel and oesophageal lining.

This increases the buffering capacity of saliva.

Question 23

L50

What happens to saliva composition when unstimulated (e.g. when sleeping)?

Answer 23

Blood flow to glands reduces.

Salivary flow drops to 0.05 ml/min.

Saliva is more hypotonic (very dilute in ions).

Leads to “morning breath” due to bacterial build-up overnight.

Question 24

L50

How does capillary hydrostatic pressure affect saliva production?

Answer 24

Higher hydrostatic pressure around glands (e.g. during eating) forces more plasma into acinar cells → more saliva produced.

Lower hydrostatic pressure (e.g. at rest) → less plasma filtered → less saliva.

Question 25

# L50 What is "primary saliva" and where is it produced?

Answer 25

Primary saliva is secreted by acinar cells. It is initially isotonic (same ion concentration as plasma). Modified by duct cells into final saliva.

Question 26

# L50 What ion transport processes occur in ductal modification of saliva?

Answer 26

Na⁺ and Cl⁻ ions are reabsorbed back into blood. K⁺ and HCO₃⁻ ions are secreted into the saliva. Water remains behind → saliva becomes hypotonic.

Question 27

# L50 How does the parasympathetic nervous system increase saliva production?

Answer 27

Releases acetylcholine (ACh). ACh binds to muscarinic receptors on salivary gland cells. Increases synthesis and secretion of mucins, enzymes, and ions. Also causes vasodilation, improving plasma ultrafiltration.

Question 28

# L50 What is the role of the CFTR channel in saliva secretion?

Answer 28

CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) helps transport Cl⁻ ions. Allows HCO₃⁻ secretion indirectly. Mutations in CFTR (as in cystic fibrosis) can impair fluid secretion → thick, sticky secretions.

Question 29

# L50 Why is bicarbonate valuable in saliva and conserved carefully?

Answer 29

Bicarbonate (HCO₃⁻) is essential for neutralising acids throughout the body. The body avoids wasting it — large amounts are only secreted during active digestion. During rest, saliva is kept bicarbonate-poor to preserve systemic acid–base balance.

Question 30

# L50 Why must saliva remain hypotonic compared to plasma? A) To dissolve more enzymes for digestion. B) To maintain hydration of oral tissues and prevent water loss. C) To improve secretion of calcium and phosphate. D) To facilitate active transport of food particles into the mouth.

Answer 30

Answer: B – Hypotonic saliva prevents dehydration of oral tissues.

Question 31

# L50 What component of saliva primarily neutralises acid in the mouth? A) Lysozyme B) α-amylase C) Bicarbonate ions (HCO₃⁻) D) Immunoglobulin A (IgA)

Answer 31

Answer: C – Bicarbonate ions provide buffering capacity.

Question 32

# L50 During unstimulated conditions (e.g. sleeping), how does saliva composition change? A) It becomes more alkaline and thicker. B) It becomes more hypotonic and low in bicarbonate. C) It becomes isotonic with blood. D) It increases in volume to flush out bacteria.

Answer 32

Answer: B – During sleep, saliva becomes more hypotonic and bicarbonate-poor.

Question 33

# L50 Which factor most directly increases plasma filtration into salivary acini? A) Increased parasympathetic firing B) Increased hydrostatic pressure in surrounding capillaries C) Release of anti-diuretic hormone (ADH) D) Inhibition of ductal sodium channels

Answer 33

Answer: B – Hydrostatic pressure drives plasma into acinar cells.

Question 34

# L50 Where is "primary saliva" produced? A) Submucosal glands B) Ductal cells C) Acinar cells D) Epithelial cells lining the tongue

Answer 34

Answer: C – Acinar cells produce the initial isotonic primary saliva.

Question 35

# L50 How is saliva modified as it passes through the ducts? A) Sodium and bicarbonate are added; water is reabsorbed. B) Sodium and chloride are reabsorbed; water remains behind. C) Potassium and chloride are removed; water is added. D) Bicarbonate and water are removed; sodium is added.

Answer 35

Answer: B – Na⁺ and Cl⁻ are reabsorbed, water stays (ducts are water-impermeable).

Question 36

# L50 What neurotransmitter mediates parasympathetic stimulation of salivary glands? A) Noradrenaline B) Adrenaline C) Acetylcholine D) Dopamine

Answer 36

Answer: C – Acetylcholine stimulates salivary secretion via muscarinic receptors.

Question 37

# L50 What is the role of the CFTR channel in saliva secretion? A) Absorbs potassium into the saliva. B) Secretes bicarbonate and chloride into the duct lumen. C) Directly reabsorbs sodium into blood. D) Blocks water movement in acinar cells.

Answer 37

Answer: B – CFTR transports chloride (and indirectly bicarbonate) into the saliva.

Question 38

# L50 Why is bicarbonate secretion increased during meals? A) To stimulate chewing reflexes. B) To neutralise gastric acid and protect oral structures. C) To improve taste perception by alkalinising saliva. D) To mineralise teeth immediately after meals.

Answer 38

Answer: B – Bicarbonate neutralises acid to protect teeth and oesophagus.

Question 39

# L50 10. What would happen if saliva became hypertonic? 11. A) Oral tissues would become swollen. B) Water would move into oral tissues, keeping them hydrated. C) Water would move out of oral tissues, causing dehydration. D) Salivary secretion volume would increase dramatically.

Answer 39

Answer: C – Hypertonic saliva would cause water loss from tongue and cheeks.

Question 40

# L54 What are the main functions of the stomach?

Answer 40

Stores food (compliant reservoir). Kills bacteria via gastric acid. Liquefies food. Mixes chyme with gastric secretions. Kneads food to particles smaller than 1 mm. Regulates release of chyme into duodenum. Produces intrinsic factor (needed for vitamin B₁₂ absorption).

Question 41

# L54 Where does most digestion occur in the gastrointestinal tract?

Answer 41

Not in the stomach! Most digestion and absorption occur in the small intestine. Stomach mainly handles preliminary breakdown and mechanical processing.

Question 42

# L54 What are the anatomical regions of the stomach?

Answer 42

Fundus. Body (corpus). Antrum. Pylorus (leading to pyloric sphincter and duodenum).

Question 43

# L54 What is the function of gastric pits?

Answer 43

Openings in the gastric mucosa leading to glands. House different specialised cells that secrete mucus, acid, enzymes, and hormones.

Question 44

# L54 What are the key stimulants of acid secretion?

Answer 44

Gastrin (hormone). Acetylcholine (ACh) (neurotransmitter from vagus nerve). Histamine (local paracrine factor).

Question 45

# L54 How do these stimulants act on the parietal cell?

Answer 45

Gastrin → CCK-B receptor. Acetylcholine → M3 muscarinic receptor. Histamine → H₂ receptor. All increase H⁺/K⁺ ATPase activity (proton pumps).

Question 46

# L54 How is hydrochloric acid (HCl) secreted by the parietal cell?

Answer 46

CO₂ + H₂O → (via carbonic anhydrase) → H₂CO₃ → HCO₃⁻ + H⁺. H⁺ is pumped into stomach lumen by H⁺/K⁺ ATPase (proton pump). Cl⁻ follows and joins H⁺ to form HCl.

Question 47

# L54 What is the "alkaline tide"?

Answer 47

After eating, bicarbonate (HCO₃⁻) is pumped into blood from parietal cells. This temporarily raises blood pH after meals.

Question 48

# L54 What hormones inhibit gastric acid secretion?

Answer 48

Somatostatin (from D cells). Secretin (from duodenal S cells). Cholecystokinin (CCK) (from duodenal I cells).

Question 49

# L54 What happens during the intestinal phase of secretion?

Answer 49

Secretin neutralises acid (by stimulating pancreatic HCO₃⁻ release). CCK inhibits gastric acid and stimulates bile and enzyme release. Overall effect: Switch off acid production once food moves into duodenum.

Question 50

# L54 What can happen if acid secretion is not properly controlled?

Answer 50

Barrett’s Oesophagus: chronic reflux changes lower oesophageal lining, pre-cancerous. Duodenal Ulcers: excessive acid damages the duodenum.

Question 51

# L54 What drugs are used to treat peptic ulcers?

Answer 51

H₂-receptor antagonists (e.g. cimetidine, ranitidine): block histamine action. Proton pump inhibitors (PPIs) (e.g. omeprazole, lansoprazole): block H⁺/K⁺ ATPase.

Question 52

# L54 What is Helicobacter pylori?

Answer 52

A bacterium associated with peptic ulcer disease (PUD) and gastric cancer. Infects gastric mucosa and increases acid injury risk. May be transmitted orally; dentists may be at higher risk.

Question 53

# L54 What are the main digestive enzymes secreted by the pancreas?

Answer 53

Proteases: digest proteins (e.g. trypsin, chymotrypsin). Lipases: digest fats. Carbohydrases: digest carbohydrates (e.g. amylase). Nucleases: digest nucleic acids.

Question 54

# L54 Why is bicarbonate secretion important in the duodenum?

Answer 54

Neutralises acidic chyme from the stomach. Prevents duodenal ulcers. Creates the optimal pH for pancreatic enzyme function.

Question 55

# L54 What stimulates acinar cell secretion?

Answer 55

Cholecystokinin (CCK): stimulates enzyme-rich secretion. CCK also contracts the gallbladder to release bile.

Question 56

# L54 What stimulates ductal cell secretion?

Answer 56

Secretin: stimulates bicarbonate-rich secretion from duct cells.

Question 57

# L54 What role does the CFTR channel have in the pancreas?

Answer 57

Allows chloride (Cl⁻) secretion into ducts, enabling bicarbonate (HCO₃⁻) exchange. Malfunction of CFTR (e.g. in cystic fibrosis) leads to thickened pancreatic secretions.

Question 58

# L54 How is the plasma "alkaline tide" after meals neutralised?

Answer 58

Pancreatic duct cells release H⁺ into the bloodstream when secreting HCO₃⁻ into the duodenum. This counterbalances the alkaline tide from gastric acid production.

Question 59

# L54 What are consequences of chronic pancreatitis?

Answer 59

Loss of pancreatic enzymes → malabsorption (proteins, fats, carbohydrates). Steatorrhoea (fatty, foul-smelling stools). Weight loss, bloating, nutritional deficiencies. Enzyme replacement therapy may be required (e.g. pancrelipase).

Question 60

# L54 What are the different types of cells in the gastric glands and what do they secrete?

Answer 60

Goblet cells and mucous neck cells secrete mucus and bicarbonate for mucosal protection. Parietal cells secrete hydrochloric acid (HCl) and intrinsic factor. Chief (zymogen) cells secrete pepsinogen, the inactive precursor of pepsin. Enterochromaffin-like (ECL) cells secrete histamine. G cells secrete gastrin. D cells secrete somatostatin.

Question 61

# L54 How does the cephalic phase stimulate acid secretion?

Answer 61

Through vagus nerve activation, which releases acetylcholine that stimulates parietal cells directly, ECL cells to release histamine, and G cells to release gastrin.

Question 62

# L54 What is Helicobacter pylori and why is it clinically important?

Answer 62

Helicobacter pylori is a bacterium that colonises the gastric mucosa, causes chronic gastritis, increases the risk of peptic ulcer disease and gastric cancer, and can be transmitted orally.

Question 63

# L54 What drugs are used to treat excessive acid secretion or peptic ulcers?

Answer 63

H2-receptor antagonists such as cimetidine and ranitidine, which block histamine-mediated acid secretion. Proton pump inhibitors (PPIs) such as omeprazole and lansoprazole, which block the H⁺/K⁺ ATPase directly.

Question 64

# L54 What are the two main functions of the pancreas?

Answer 64

Exocrine function: secretion of digestive enzymes and bicarbonate-rich fluid into the duodenum. Endocrine function: secretion of hormones such as insulin, glucagon, and somatostatin into the bloodstream.

Question 65

# L54 Why is bicarbonate secretion by the pancreas important?

Answer 65

It neutralises the acidic chyme entering the duodenum from the stomach. It prevents damage to the duodenal mucosa. It provides the correct alkaline pH environment for digestive enzymes to work optimally.

Question 66

# L54 1. Which type of epithelium lines the stomach? A) Stratified squamous B) Simple cuboidal C) Simple columnar D) Transitional

Answer 66

✅ Answer: C – Simple columnar epithelium.

Question 67

# L54 At the gastro-oesophageal junction, which epithelial transition occurs? A) Simple columnar to pseudostratified columnar B) Stratified squamous to simple columnar C) Simple cuboidal to simple columnar D) Stratified squamous to stratified cuboidal

Answer 67

Answer: B – Stratified squamous to simple columnar.

Question 68

# L54 What is the function of parietal cells in the stomach? A) Secretion of pepsinogen B) Secretion of mucus C) Secretion of hydrochloric acid and intrinsic factor D) Absorption of nutrients

Answer 68

Answer: C – Secretion of hydrochloric acid and intrinsic factor.

Question 69

# L54 Which cell type secretes pepsinogen in the gastric glands? A) Parietal cells B) Goblet cells C) Enteroendocrine cells D) Chief cells

Answer 69

Answer: D – Chief cells.

Question 70

# L54 Which hormone is secreted by enteroendocrine cells in the stomach? A) Secretin B) Insulin C) Gastrin D) Somatostatin

Answer 70

Answer: C – Gastrin.

Question 71

# L54 What is the function of gastrin? A) Neutralises acid B) Stimulates HCl secretion by parietal cells C) Digests proteins D) Absorbs vitamin B₁₂

Answer 71

Answer: B – Stimulates HCl secretion by parietal cells.

Question 72

# L54 Which region of the stomach contains the most acid-secreting cells? A) Cardia B) Fundus C) Pylorus D) Lesser curvature

Answer 72

Answer: B – Fundus (also body).

Question 73

# L54 What is the function of mucous neck cells in the stomach? A) Absorb glucose B) Secrete pepsinogen C) Secrete a thinner, acidic form of mucus D) Secrete alkaline mucus

Answer 73

Answer: C – Secrete a thinner, acidic form of mucus.

Question 74

# L54 Which of the following correctly pairs a stomach cell with its secretion? A) Goblet cell – pepsinogen B) Chief cell – intrinsic factor C) Parietal cell – HCl D) Enteroendocrine cell – mucus

Answer 74

Answer: C – Parietal cell – HCl.

Question 75

# L54 What is the function of the pancreatic acini? A) Hormone storage B) Enzyme synthesis for digestion C) Fat absorption D) Vitamin D activation

Answer 75

Answer: B – Enzyme synthesis for digestion.

Question 76

# L54 What is the role of the Islets of Langerhans? A) Secretion of bile B) Enzyme storage C) Secretion of hormones like insulin and glucagon D) Fat absorption

Answer 76

Answer: C – Secretion of hormones like insulin and glucagon.

Question 77

# L54 Which pancreatic cell secretes insulin? A) Alpha cell B) Beta cell C) Delta cell D) Acinar cell

Answer 77

Answer: B – Beta cell.

Question 78

# L54 Which of the following is an exocrine function of the pancreas? A) Glucagon secretion B) Insulin secretion C) Amylase secretion D) Somatostatin secretion

Answer 78

Answer: C – Amylase secretion.

Question 79

# L54 Which of the following is found in the pancreatic duct system? A) Bile canaliculi B) Sinusoids C) Centroacinar cells D) Enterocytes

Answer 79

Answer: C – Centroacinar cells.

Question 80

# L54 Which histological feature helps distinguish endocrine from exocrine pancreas on microscope slides? A) Presence of ducts B) Pale-staining Islets of Langerhans C) Basophilic cytoplasm D) Tight junctions

Answer 80

Answer: B – Pale-staining Islets of Langerhans.

Question 81

# L54 What is the consequence of parietal cell loss (e.g., in autoimmune gastritis)? A) Hypersecretion of insulin B) Protein malabsorption C) Vitamin B₁₂ deficiency D) Increase in bile secretion

Answer 81

Answer: C – Vitamin B₁₂ deficiency (due to loss of intrinsic factor).

Question 82

# L54 What triggers pancreatic secretion of digestive enzymes? A) Secretin and CCK from the duodenum B) Gastrin from the stomach C) Intrinsic factor D) Acid from the ileum

Answer 82

Answer: A – Secretin and CCK from the duodenum.

Question 83

# L54 Which of the following correctly describes the organisation of the pancreas? A) Mostly endocrine with a small exocrine portion B) Entirely endocrine C) Mostly exocrine with scattered endocrine clusters D) Entirely exocrine

Answer 83

Answer: C – Mostly exocrine with scattered endocrine clusters.

Question 84

# L54 Which of the following best describes the epithelium of the stomach? A) Stratified squamous non-keratinised B) Simple cuboidal C) Simple columnar D) Pseudostratified columnar ciliated

Answer 84

Answer: C – Simple columnar

Question 85

# L54 Which region of the stomach contains mucous cells but few acid-producing cells? A) Fundus B) Body C) Pylorus D) Cardia

Answer 85

✅ Answer: D – Cardia

Question 86

# L54 What do chief cells secrete? A) Hydrochloric acid B) Pepsinogen and gastric lipase C) Intrinsic factor D) Somatostatin

Answer 86

Answer: B – Pepsinogen and gastric lipase

Question 87

# L54 Which hormone is released by G cells in the stomach? A) Secretin B) Gastrin C) Glucagon D) Ghrelin

Answer 87

Answer: B – Gastrin

Question 88

# L54 In the pancreas, which part is responsible for endocrine secretion? A) Acinar cells B) Centroacinar cells C) Islets of Langerhans D) Ductal cells

Answer 88

Answer: C – Islets of Langerhans

Question 89

# L54 Which hormone is secreted by pancreatic alpha cells? A) Insulin B) Glucagon C) Somatostatin D) Pancreatic polypeptide

Answer 89

Answer: B – Glucagon

Question 90

# L54 What is the function of pancreatic acini? A) Secrete insulin B) Secrete digestive enzymes into ducts C) Secrete bile D) Absorb nutrients

Answer 90

Answer: B – Secrete digestive enzymes into ducts

Question 91

# L54 Which stain would best differentiate endocrine and exocrine regions in the pancreas histologically? A) H&E B) PAS C) Masson’s trichrome D) Silver stain

Answer 91

Answer: A – H&E (endocrine lighter staining, exocrine darker)

Question 92

# L54 A 52-year-old man with chronic acid reflux undergoes endoscopy. Biopsy reveals columnar epithelium with goblet cells in the distal oesophagus. What is the most likely diagnosis? A) Squamous cell carcinoma B) Barrett’s oesophagus C) Achalasia D) Acute gastritis

Answer 92

Answer: B – Barrett’s oesophagus

Question 93

# L54 A patient is found to have decreased intrinsic factor production. What vitamin deficiency will they most likely develop? A) Vitamin C B) Vitamin D C) Vitamin B₁₂ D) Folate

Answer 93

Answer: C – Vitamin B₁₂

Question 94

# L54 A 65-year-old male presents with recurrent peptic ulcers. Biopsy reveals a gastrin-secreting tumour in the pancreas. What is the most likely diagnosis? A) Zollinger–Ellison syndrome B) Crohn’s disease C) Barrett’s oesophagus D) Insulinoma

Answer 94

Answer: A – Zollinger–Ellison syndrome

Question 95

# L54 A 19-year-old is diagnosed with Type 1 diabetes. Which pancreatic cells have been destroyed? A) Alpha cells B) Beta cells C) Delta cells D) Acinar cells

Answer 95

Answer: B – Beta cells

Question 96

# L54 A biopsy of gastric mucosa shows loss of parietal cells. What consequence is most likely to follow? A) Duodenal ulcer B) Malabsorption of glucose C) Vitamin B₁₂ deficiency anaemia D) Excess gastrin

Answer 96

Answer: C – Vitamin B₁₂ deficiency anaemia (pernicious anaemia)

Question 97

# L54 A pathology slide of the pancreas shows a pale-staining region with no ducts. Which function is most likely associated with this region? A) Bicarbonate secretion B) Enzyme release C) Hormone release into bloodstream D) Mucus production

Answer 97

Answer: C – Hormone release into bloodstream (Islets)

Question 98

# L54 A 45-year-old woman with steatorrhoea is found to have pancreatic exocrine insufficiency. What enzyme is she most likely deficient in? A) Lactase B) Pepsin C) Lipase D) Amylase

Answer 98

Answer: C – Lipase

Question 99

# L54 Which of the following combinations is correct? A) Fundus – Goblet cells B) Chief cells – HCl C) Parietal cells – Intrinsic factor D) G cells – Pepsinogen

Answer 99

Answer: C – Parietal cells – Intrinsic factor

Question 100

# L54 Which region of the pancreas contains the highest number of insulin-producing cells? A) Acinar region B) Periphery of lobules C) Islets of Langerhans (mainly central beta cells) D) Intercalated ducts

Answer 100

Answer: C – Islets of Langerhans

Question 101

# L54 Where would you expect to find Brunner’s glands? A) Gastric mucosa B) Pyloric sphincter C) Duodenum submucosa D) Pancreas

Answer 101

Answer: C – Duodenum submucosa

Question 102

# L54 Which enzyme is secreted by chief cells and becomes active in acidic pH? A) Trypsin B) Pepsin C) Lipase D) Amylase

Answer 102

Answer: B – Pepsin (from pepsinogen)

Question 103

# L54 A tumour in the tail of the pancreas is most likely to affect which function first? A) Enzyme secretion B) Insulin secretion C) Bile transport D) Acid production

Answer 103

Answer: B – Insulin secretion (Islets are more concentrated in the tail)

Question 104

# L54 Where is the pancreas located and what is its structure AND are the two functional components of the pancreas?

Answer 104

Exocrine (acinar and duct cells – 99%) and endocrine (islets of Langerhans – 1%)​

Question 105

# L54 What is the composition of pancreatic juice?

Answer 105

Alkaline fluid (HCO₃⁻) and digestive enzymes: proteases, lipases, amylases, nucleases​

Question 106

# L54 What stimulates enzyme secretion from acinar cells?

Answer 106

Cholecystokinin (CCK), secretin and acetylcholine (ACh)​

Question 107

# L54 What is the role of HCO₃⁻ in pancreatic juice?

Answer 107

What is the role of HCO₃⁻ in pancreatic juice?

Question 108

# L54 Which channel is responsible for HCO₃⁻ secretion into the ductal lumen?

Answer 108

CFTR (Cystic Fibrosis Transmembrane Conductance Regulator)​

Question 109

# L54 Which hormones are secreted by the islets of Langerhans?

Answer 109

Insulin, glucagon, and somatostatin

Question 110

# L54 What are the phases of pancreatic secretion control?

Answer 110

Cephalic Phase: neural (vagus nerve/ACh) Gastric Phase: distension/protein leads to ACh and gastrin Intestinal Phase: acid/fatty chyme triggers secretin and CCK​ .

Question 111

# L54 What does secretin stimulate?

Answer 111

HCO₃⁻ secretion from duct cells and inhibition of gastric acid secretion.

Question 112

# L54 What does CCK stimulate?

Answer 112

Enzyme secretion from acinar cells, bile release from gallbladder, and inhibition of gastric acid​

Question 113

# L54 When does pancreatic insufficiency become clinically evident?

Answer 113

When enzyme secretion drops below 10% of normal (90% function loss)

Question 114

# L54 What are symptoms of chronic pancreatitis?

Answer 114

Steatorrhoea, weight loss, bloating, cramps, foul-smelling stools, malabsorption​

Question 115

# L54 How is chronic pancreatic insufficiency managed?

Answer 115

Oral pancreatic enzyme replacement with acid-resistant pellets during meals.

Question 116

# L54 Where does the pancreatic duct empty its contents?

Answer 116

Into the duodenum at the Ampulla of Vater, where it merges with the bile duct

Question 117

# L54 Why is the pancreas described as having a 'functional reserve'?

Answer 117

Because symptoms of insufficiency only appear when 90% of its exocrine function is lost​

Question 118

# L54 What is the function of each class of digestive enzyme in pancreatic juice?

Answer 118

Proteases: digest proteins (e.g. trypsin) Lipases: digest fats Carbohydrases: digest carbohydrates Nucleases: digest nucleic acids​

Question 119

# L54 Why is alkaline secretion important for enzyme function?

Answer 119

It neutralises acidic chyme and provides the right pH for pancreatic enzymes to function optimally​

Question 120

# L54 What is the difference in secretion between duct and acinar cells?

Answer 120

Acinar cells secrete digestive enzymes (stimulated mainly by CCK). Duct cells secrete HCO₃⁻ (stimulated by secretin) and require CFTR for Cl⁻/HCO₃⁻ exchange

Question 121

# L54 Acinar cells secrete digestive enzymes (stimulated mainly by CCK). What happens to HCO₃⁻ in the plasma during digestion?

Answer 121

It neutralises the 'alkaline tide' caused by gastric HCl production, maintaining plasma pH

Question 122

# L54 How do pancreatic secretions interact with gastric acid secretion?

Answer 122

Secretin and CCK from the duodenum inhibit gastric HCl secretion while stimulating pancreatic HCO₃⁻ and enzyme release​

Question 123

# L54 What role does ACh play in pancreatic secretion?

Answer 123

ACh stimulates both enzyme and bicarbonate secretion via vagal (parasympathetic) input, particularly in the cephalic and gastric phases​

Question 124

# L54 What is the role of CFTR in cystic fibrosis affecting the pancreas?

Answer 124

Defective CFTR impairs HCO₃⁻ and Cl⁻ transport, leading to thickened secretions, duct blockage, and pancreatic insufficiency

Question 125

# L54 Why must pancreatic enzyme supplements be acid-resistant?

Answer 125

To prevent degradation by stomach acid and ensure release at intestinal pH (around 5.0–5.5)​

Question 126

# L54 Why is the pancreas crucial for fat digestion?

Answer 126

It provides both lipases and HCO₃⁻. Lipases break down fat, while HCO₃⁻ neutralises stomach acid, enabling bile salts to form micelles — essential for lipid absorption

Question 127

# L54 How is the ‘alkaline tide’ from the stomach neutralised?

Answer 127

Pancreatic HCO₃⁻ enters the duodenum to neutralise gastric acid, and pancreatic H⁺ enters the plasma to offset HCO₃⁻, stabilising blood pH​

Question 128

# L54 What is the role of secretin in pancreatic function?

Answer 128

Secretin stimulates ductal HCO₃⁻ secretion and inhibits gastric acid secretion. It’s released in response to acidic chyme entering the duodenum

Question 129

# L54 What stimulates CCK release and what does it do?

Answer 129

Lipids in the duodenum stimulate I-cells to release CCK. CCK causes enzyme secretion from the pancreas, gallbladder contraction, and inhibits gastric emptying and acid secretion

Question 130

# L54 What dual role does the CFTR channel play in pancreatic ducts?

Answer 130

CFTR transports Cl⁻ and HCO₃⁻ into the ductal lumen. Its activity is essential for creating an alkaline, enzyme-permissive environment​

Question 131

# L54 Why does CFTR malfunction lead to pancreatic insufficiency in cystic fibrosis?

Answer 131

Impaired secretion of Cl⁻ and HCO₃⁻ leads to viscous secretions, blocked ducts, and insufficient delivery of enzymes and HCO₃⁻ to the duodenum​

Question 132

# L54 What are signs of pancreatic insufficiency?

Answer 132

Steatorrhoea, weight loss, foul-smelling greasy stool, bloating, and malabsorption​

Question 133

# L54 How are enzyme replacements designed to avoid inactivation by stomach acid?

Answer 133

They are encapsulated in acid-resistant pellets that release contents at intestinal pH 5.0–5.5​

Question 134

# L54 Where does the pancreatic duct release its contents? A. Jejunum B. Stomach C. Duodenum D. Ileum

Answer 134

Correct answer: C. Duodenum

Question 135

# L54 Which of the following best describes the pancreas? A. Intraperitoneal, soft, segmented B. Retroperitoneal, lobulated, exo- and endocrine gland C. Retroperitoneal, muscular, purely endocrine D. Intraperitoneal, fatty, exocrine only

Answer 135

Correct answer: B. Retroperitoneal, lobulated, exo- and endocrine gland

Question 136

# L54 What is the main stimulus for enzyme secretion from pancreatic acinar cells? A. Secretin B. Gastrin C. Cholecystokinin (CCK) D. Insulin

Answer 136

Correct answer: C. Cholecystokinin (CCK)

Question 137

# L54 What is the function of HCO₃⁻ in pancreatic juice? A. Stimulates pepsinogen B. Neutralises acidic chyme C. Emulsifies fat D. Activates trypsinogen

Answer 137

Correct answer: B. Neutralises acidic chyme

Question 138

# L54 Which channel is crucial for bicarbonate secretion into the pancreatic ducts? A. Sodium-potassium pump B. GLUT-2 C. CFTR D. Aquaporin-4

Answer 138

Correct answer: C. CFTR

Question 139

# L54 The endocrine pancreas is primarily composed of: A. Duct cells B. Acinar clusters C. Islets of Langerhans D. Goblet cells

Answer 139

Correct answer: C. Islets of Langerhans

Question 140

# L54 Which hormone from the pancreas lowers blood glucose levels? A. Glucagon B. Insulin C. Somatostatin D. Gastrin

Answer 140

Correct answer: B. Insulin

Question 141

# L54 Which of the following phases of digestion involves vagal stimulation of pancreatic secretion? A. Gastric phase B. Cephalic phase C. Intestinal phase D. Colonic phase

Answer 141

Correct answer: B. Cephalic phase

Question 142

# L54 What triggers secretin release from the duodenum? A. Proteins in the stomach B. Fats in the colon C. Acidic chyme in the duodenum D. Bile salts

Answer 142

Correct answer: C. Acidic chyme in the duodenum

Question 143

# L54 What are the actions of CCK? (Select all that apply) A. Inhibits gastric emptying B. Stimulates bile release C. Inhibits insulin secretion D. Stimulates pancreatic enzyme release

Answer 143

Correct answers: A, B, D

Question 144

# L54 Pancreatic insufficiency typically becomes symptomatic after: A. 10% function loss B. 50% function loss C. 70% function loss D. 90% function loss

Answer 144

Correct answer: D. 90% function loss

Question 145

# L54 Which of the following is NOT a feature of pancreatic insufficiency? A. Weight loss B. Steatorrhoea C. Constipation D. Bloating

Answer 145

Correct answer: C. Constipation

Question 146

# L54 Which pancreatic condition is common in cystic fibrosis due to defective CFTR? A. Hyperinsulinaemia B. Enzyme hypersecretion C. Duct blockage and pancreatic insufficiency D. Increased gastric acid secretion

Answer 146

Correct answer: C. Duct blockage and pancreatic insufficiency

Question 147

# L54 Why are enzyme replacement therapies enteric-coated? A. To increase absorption in the stomach B. To survive acid and release in the duodenum C. To bypass liver metabolism D. To prevent allergic reactions

Answer 147

Correct answer: B. To survive acid and release in the duodenum